Abstract:
Using thioacetamide (TAA) as precursor, homogeneous and steady monodispersed CdS nanocrystals were synthesized in Perfluorinated Ionomer Membranes (Nafion) by self-assembly. Unlike the ionic precursors such as Na2S and H2S, TAA could diffuse into the cationic- exchangeable ionomer membranes much more uniformly, which led to the homogeneous distribution of CdS nanoparticles in the Nafion membranes. High resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDXA) were used to investigate the synthesis mechanism, the size distribution and the microstructure of these CdS nanoparticles embedded in Nafion membranes. Optical properties of CdS nanoparticles in Nafion were also characterized by UV-Vis absorption and luminescence spectra. The results show that the quantum size effect becomes strong with the decrease of the size of CdS nanocrystals. Blue shift appears both on the absorb edges in the absorption spectra and on the band- edge emission in the luminescence spectrum.